The present invention relates to a sampling tube for obtaining molten metal samples and apparatus for use in removing specimen gas from the resultant sample.
In the determination of the content of molten metal, such as during a steel manufacturing process, it is desirable to monitor the content of the melt during various stages of production. A variety of sampling devices have been suggested, particularly for use with specimen gases such as hydrogen, which is particularly difficult to sample and determine inasmuch as gaseous hydrogen can easily escape while residual hydrogen remains in the solid specimen removed by the sampling device. U.S. Pat. No. 3,967,505 discloses one sampling structure for the removal of a sample from a molten metal in an effort to capture the total hydrogen content of a sample. The structure disclosed provides a pair of evacuated chambers divided into upper and lower sections by a porous plug and which includes a restricted entryway such that as the sample is removed it solidifies to seal the sampling tube. The construction of the sampling device disclosed in this patent is somewhat complicated and expensive involving several interfitted parts.